1. Field of the Invention
The present invention is directed to an apparatus for disintegrating solid waste to form a pulp for disposal.
2. Description of the Related Art
Waste reduction systems such as solid waste pulpers have been in use for many years. One such system is disclosed in Altonji et al., U.S. Pat. No. 5,577,674, assigned to the assignee of this application, the disclosure of which is incorporated herein by reference. In typical systems such as that in U.S. Pat. No. 5,577,674, waste from a kitchen or another waste source is placed into a pulping tank partially filled with water. A cutting or grinding mechanism is installed near the bottom of the tank and usually includes a rotating impeller with attached rotating blades that periodically come into play with stationary blades attached to a sieve ring. A grinding motor rotates the impeller, causing the blades to grind the solid waste into a pulp of small particles and circulate the water and solids within the tank. Waste particles that are sufficiently small to pass through the sieve ring are discharged from the tank and away from the pulping unit to an extractor to remove water from the slurry. In close-coupled systems such as in U.S. Pat. No. 5,577,674, the force of the rotating blade and a set of pumping ears are used to move the slurry a short distance to the extractor. In many prior art pulping systems, a slurry pump having a separate drive from the grinding motor is used to pump the slurry to a remote extractor.
Traditionally, the pulping capacity, or how much waste a pulper can process in a given period of time, has been thought to depend on the size of the pulper's components, specifically, the pulping tank volume and the rotating blade diameter. If a large pulping capacity was needed, a large tank and a large rotating blade were provided.
The slurry is usually sent to a liquid extractor for drawing water out of the slurry and returning the extracted water to the tank. In some pulping systems, a portion of the extracted water, or “return water,” is directed to a feed tray where the solid waste is placed. The return water is used to flush the solids down the tray into the pulping tank.
Different downstream environments for pulpers and extractors are common in waste reduction systems. One is a close-coupled system, where the pulper and extractor are in close proximity to each other so that the slurry does not need to be pumped very far, usually a few feet or less, to reach the extractor. Another is a remote system where the pulper and extractor are not in close proximity and the slurry pump must move the slurry a much greater distance, as much as 100 feet or more.
It has been necessary for the pulping system to be designed depending on whether a close-coupled or a remote system will be used by a particular customer, and what type of pulping it will be used for. For example, two restaurants may order the same pulper and extractor, but place them in different configurations so that one restaurant has a remote system where the pulper and extractor might be 100 feet apart and the other has a close-coupled system that requires a pump with a much lower pumping capacity than the first restaurant. Different pumping capacities are needed in different pulping situations as well. One customer may need a system to pulp large amounts of heavy material so that the slurry pump or pumping ears are required to move more dense slurry than another customer who may not have as intense pulping needs.
Because of varying customer needs like the above examples, a supplier typically has been required to maintain an inventory of pumps or pumping ears of various capacities so that the system will provide the desired flow rate for the anticipated slurry. In the above examples, the supplier would have to have an inventory with at least a high capacity slurry pump for the pulper of the first restaurant, and a low capacity slurry pump or set of pumping ears for the pulper of the second restaurant.
A problem that can occur with pulpers is the buildup of fibrous debris at the sieve ring or rotating blades. This buildup, also known as “bridging” or “logjamming,” can cause blockage of the sieve ring that can back up the pulping system which can have a negative impact on the pulping efficiency of the system.
Another problem associated with many pulpers is the translation of vibrations between the pulping tank and its surroundings, particularly to the frame of the pulper. In an exemplary case of this problem, pulpers may include a table as part of the frame so that a restaurant's employees may place dishes on the table to conserve space. As the pulper is used, vibration is translated to the frame from the tank, and then to the table, causing the dishes to vibrate. This can be very noisy as the dishes vibrate and clatter. This is very undesirable for the restaurant, as it is annoying and distracting to the customers and the employees.
Yet another problem that can occur with pulpers has to do with the feed tray. Many pulping systems operate at a flow rate which results in a turbulent, splashing flow of the return water within the feed tray. At high enough flow rates, the return water can splash wildly out of the tray. This would also be undesirable because the mess must be cleaned up repeatedly.
What is needed is a pulper that allows for easy modification between close-coupled systems and remote systems. Also what is needed is a pulper that keeps fibrous debris clear of the sieve ring and rotating blade to prevent blockage and backup of the pulping system. Further, what is needed is a pulper that minimizes the translation of vibrations between the pulping tank and its surroundings. Additionally, what is needed is a feed tray that minimizes splashing in the feed tray.